Having an anxiety disorder in youth is associated with a higher likelihood of developing a psychological disorder in adulthood. Treating youth with anxiety disorders may reduce the likelihood of anxiety, depressive, and substance use disorders later in life. This study is designed to evaluate long-term outcomes associated with treatment for childhood anxiety by comparing successfully and unsuccessfully treated participants fifteen years after the completion of treatment. A sample of 118 youth who had been diagnosed with an anxiety disorder and who had been randomized to treatment in a randomized clinical trial (reported in Kendall et al., 1997) will be invited to participate. Participants will have been randomized to treatment 15 years prior and will participate in a half-day evaluation on one occasion. The evaluation will include paper-and- pencil self-report measures and a diagnostic interview conducted to assess for anxiety levels, depressive symptoms, and substance use since the last evaluation. Information regarding functional impairment and life events since therapy will also be gathered and evaluated. To test the effect of previous treatment outcome on the sequelae of anxiety, Logistic and linear regression will be conducted to examine whether outcome status (successful/unsuccessful as indicated by posttreatment diagnostic status) predicts adult anxiety, depressive symptoms/disorder and subsequent substance use/abuse since the time of the last evaluation. Both self-reported symptoms and diagnostic status will be examined. The present study will be the first to assess the long-term effects of treatment for an anxiety disorder in youth on anxiety, depression, and substance abuse through the period of young adulthood when these disorders are often seen. PUBLIC HEALTH RELEVANCE: The present study will be the first to assess the long-term effects of treatment for an anxiety disorder in youth on anxiety, depression, and substance misuse/abuse through the period of young adulthood when these disorders are often seen. This is important from a public health perspective because it will inform if there are advantages to early intervention of anxiety on negative sequelae of the disorder (e.g., substance misuse/abuse, depression) in adulthood. Knowledge about any advantageous effects of an anxiety intervention will provide important insight regarding prevention of secondary disorders by treating a primary disorder.